A research program has been established to develop and evaluate a short term (days to weeks) pneumatic ventricular assist pump and a long-term (greater than two year) implantable electric ventricular assist pump. The program has focused on a close interaction and cooperation between a dedicated group of physicians, engineers, veterinarians and technical personnel. The pneumatic assist pump, designed and built in our laboratories and first used in the clinical setting at our University Hospital in 1976, will be employed in patients with acute heart failure following open heart operations, as a "bridge" for transplantation, and following myocardial infarction with shock. Specific attention will be directed toward indication for pump use, restoration of adequate hemodynamics, the identification and treatment of right heart failure, role of anticoagulants and antiplatelet drugs, and long-term results. Certain patients with irreversible, end stage left ventricular failure require long-term left ventricular support. An implantable, electrically powered, assist pump has been under development for the treatment of such patients. A compact, custom designed, brushless DC motor is used to rotate the nut of a highly efficient long-life roller screw, thus converting electrical energy to actuate the pusher plate of a blood pump. A prototype system, with external electronics and percutaneous wire electrical transmission, has been evaluated in animal studies. We now propose to refine the system by using transcutaneous (wireless) energy transfer (inductive coupling) which requires further miniaturization and implantation of control electronics. Detailed engineering analysis will be performed to evaluate flow patterns, system performance, and control mechanisms. The motor driven left ventricular assist pump will be implanted in normal animals, animals with the mitral valve occluded and those with profound left ventricular failure. We will study the physiological effects of assist pumping, the host-prosthetic pump interaction, and the system reliability. Our goal of this phase of the assist pump program is to complete the engineering and physiologic testing to be ready for initial patient use at the completion of the proposed grant period.